REstoring the Loess Hills
This article first appeared in INHF's Fall 2008 magazine.
by Stan Buman
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| Left: Shimek's photo, taken about 100 years after the Lewis and Clark expedition, still shows treeless hill slopes. Right: Approximately 100 years after Shimek's visit, Stan Buman photographed the same Loess Hills site. Dense, woody vegetation now obstructs the former prairie and the view. Photo permission granted by the University of Iowa, The Shimek Photographic Collection, Depts. of Geoscience and Biological Sciences |
On July 16th, 1804 – while traveling along what’s now Waubonsie State Park in southwest Iowa – William Clark (Lewis and Clark expedition) noted the absence of trees when describing “an extensive prarie on the S.S.. This Prarie I call Ball [bald] pated Prarie from a range of Ball Hills parralel to the river & at from 3 to 6 miles distant from it, and extend as far up and down as I can see. [sic]”
Modern visitors to Iowa’s Loess Hills see a very different view. While the region’s steep slopes kept many native prairie remnants from succumbing to the plow, woody vegetation has slowly crept into this ancient prairie and choked out its grasses and forbs. However, both public and private landowners are attacking these invaders to maintain our historical prairies and retain the wide open vistas.
Declining grasslands
Prior to European settlement, grasslands burned frequently due to lightning strikes and fires set by Native Americans. These frequent fires confined most woody vegetation to the wetter ravines and the cooler, damper northeast-facing slopes. Early settlers did not understand fire’s ecological role in maintaining the plant and wildlife diversity on grasslands. Nor did they like seeing their homes and crops burn. Therefore, fire suppression tactics were put into place. Tillage, heavy grazing, roads and other human disturbances on the landscape also reduced the risk of wildfires burning extensive areas.
An unintended side effect was the slow encroachment of trees out of the ravines and over the ridges. The pace is so gradual, taking decades or even generations, that most people do not notice the change.
Images of change
Luckily, historical photos remain that remind us of the vast grasslands that once existed. Though members of the Lewis and Clark expedition could not photographically document the Loess Hills’ appearance in 1804, Bohumil Shimek photographed the region between 1903 and 1910. Shimek (1861 - 1937) was a professor of botany at the University of Iowa and an early leader in Iowa conservation.
In 2006, I made numerous trips to the Hills, searching for the scenes depicted in Shimek’s photos. The job was more difficult than I expected – partly because of Shimek’s vague captions but mostly because the many distinguishing features have been completely masked by trees.
Restoring the landscape
Fortunately, prairie plants are somewhat forgiving of being suppressed by the woody vegetation. Barely eking out an existence under the dense canopy, the grasses and forbs thrive following brush removal and the resulting penetration of sunlight.
Grand vistas that were once masked by a wall of brush and cedar are once again open. The park-like settings of oak savannas are being recreated as the under-story brush is removed. These efforts increase habitat required by grassland birds. Wildflowers reclaim their former slopes, creating a bouquet of color throughout the growing season. Meanwhile, increased quantity and quality of available forage in pastures can improve cattle herd economics. Grazing can be a good management tool if used wisely. Like rehabilitating an old car, restoration of the prairie requires thought and hard work. Each also requires regular maintenance to function properly. Through proper management and regular maintenance, the open prairie vistas can be restored. Plant and animal species witnessed by Lewis and Clark can once again gain ground in the Loess Hills.
Bald is beautiful!
Many local landowners aided me in identifying the location of the scenes depicted in Shimek’s images – a challenge when the landscape features are so altered. Here only scattered trees can be seen on the hill slopes.
Today small prairie remnants (foreground) struggle to survive as woody vegetation (background) crowds the slopes. The encroachment is the result of doing nothing – no woody vegetation management.
Left: Shimek, early 1900s. Right: Buman 2006
Photo permission granted by the University of Iowa, The Shimek Photographic Collection, Depts. of Geoscience and Biological Sciences
Left: Shimek, early 1900s. Shimek described this photo location as "north of Missouri Valley."
Right: Buman 2006. Today, however, much of this ridge is in the Missouri Valley. The hill was mined and its soil was used as fill material underneath interstate 29.
Photo permission granted by the University of Iowa, The Shimek Photographic Collection, Depts. of Geoscience and Biological Sciences
Stan Buman is the owner of Fenceline Photos and part-owner and Vice-president of Agren, Inc., both Iowa-based companies. To see more of his work, visit www.fencelinephotos.com.
